How can I erase a DVD-RW disc?

I got Windows 7 Home Premium and I usually use Freemake to burn my video compilation and data discs. I also have some DVD-RW discs that are not empty and I want to erase them to re-use them. Is there a way within W7 or another free software that may enable me to perform this task. Thanks in advance!

What version of windows 7you got Xhi? For some reason I am missing that option / feature in Windows 7 Home premium and trust me, it IS a legit copy of it. I really wonder what is going on. I've tried everything (I think) so far without any luck...

It's not exactly intuitive, but it works. Still wondering why he does not have the Erase Disk on his W-7. However I note that if I put the R/W disk in my ROM drive and not the RE-Writable drive the erase function IS NOT THERE!. If that is also his problem then even ImgBurn will not help

Yes I have both a DVD-ROM and a DVD-RW drive in my computer. If I put the R/W disk in the DVD R/W I get the Erase Disk button pictured above. When doing the same thing with the DVD-ROM drive the Erase button is not there.